code: def plot_angle(ax, pos, angle, length=0.95, acol="C0", **kwargs):
      vec2 = np.array(
          [np.cos(np.deg2rad(angle)), np.sin(np.deg2rad(angle))]
      )
      xy = np.c_[[length, 0], [0, 0], vec2 * length].T + np.array(pos)
      ax.plot(*xy.T, color=acol)
      return AngleAnnotation(pos, xy[0], xy[2], ax=ax, **kwargs)
  
file_path: matplotlib/galleries/examples/text_labels_and_annotations/angle_annotation.py
imports: import matplotlib.pyplot
  import numpy
  from matplotlib.patches import Arc
  from matplotlib.transforms import Bbox, IdentityTransform, TransformedBbox
label_desc: Use image node_id 1 for calling a global function with example usage: plot_angle(ax, pos, angle, length, acol) and returns: AngleAnnotation